scholarly journals The application of synchronous detector in inductive flow transducer

2017 ◽  
pp. 20-25
Author(s):  
Alexey V. Mantsurov ◽  
Keyword(s):  
Synchronous Detector ◽  
Flow Transducer

Study of a modified non-contact Hall sensor-based flow transducer using centrifugal and momentum force principle

2021 ◽  
Author(s):  
Sirshendu Saha ◽  
Saikat Kumar Bera ◽  
Saurabh Pal ◽  
Satish Chandra Bera
Keyword(s):  
Hall Sensor ◽  
Flow Transducer

scholarly journals Mechanisms of calcitonin gene-related peptide-induced increases of pulmonary blood flow in fetal sheep

2000 ◽  
Vol 279 (4) ◽  
pp. H1654-H1660 ◽  
Author(s):  
Yasushi Takahashi ◽  
Maartje De Vroomen ◽  
Christine Roman ◽  
Michael A. Heymann
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Pulmonary Blood Flow ◽  
Pulmonary Arteries ◽  
Calcitonin Gene Related Peptide ◽  
Fetal Sheep ◽  
Nitric Oxide Synthase Inhibitor ◽  
Flow Transducer ◽  
Related Peptide ◽  
Calcitonin Gene

Fetal pulmonary blood flow is regulated by various vasoactive substances. One, calcitonin gene-related peptide (CGRP), increases pulmonary blood flow. We examined four key physiological mechanisms underlying this response using the blocker drugs CGRP receptor blocker (CGRP8–37), nitric oxide synthase inhibitor [ N ω-nitro-l-arginine (l-NNA)], adenosine triphosphate-dependent potassium (KATP) channel blocker (glibenclamide), and cyclooxygenase inhibitor (indomethacin) in 17 near-term fetal sheep. Catheters were placed in the left (LPA) and main pulmonary arteries, and an ultrasonic flow transducer was placed around the LPA to measure flow continuously. CGRP was injected directly into the LPA (mean 1.02 μg/kg) before and after blockade, and responses to CGRP were statistically compared. Before blockade, CGRP increased LPA blood flow from 23 ± 25 to 145 ± 77 ml/min (means ± SD), and these increases were significantly attenuated by CGRP8–37( n = 6; 91% inhibition), l-NNA ( n = 6; 86% inhibition), and glibenclamide ( n = 6; 69% inhibition). No significant changes were found with indomethacin ( n = 6; 4% inhibition). Thus, in the fetal pulmonary circulation, CGRP increases pulmonary blood flow not only through its specific receptor but also, in part, through nitric oxide release and KATP channel activation.

scholarly journals Cinaciguat, a soluble guanylate cyclase activator, causes potent and sustained pulmonary vasodilation in the ovine fetus

2009 ◽  
Vol 297 (2) ◽  
pp. L318-L325 ◽  
Author(s):  
Marc Chester ◽  
Pierre Tourneux ◽  
Greg Seedorf ◽  
Theresa R. Grover ◽  
Jason Gien ◽  
...  
Keyword(s):  
Blood Flow ◽  
Pulmonary Hypertension ◽  
Pulmonary Artery ◽  
Pulmonary Vascular Resistance ◽  
Vascular Resistance ◽  
Guanylate Cyclase ◽  
Soluble Guanylate Cyclase ◽  
Left Pulmonary Artery ◽  
Flow Transducer ◽  
Pulmonary Vasodilation

Impaired nitric oxide-cGMP signaling contributes to severe pulmonary hypertension after birth, which may in part be due to decreased soluble guanylate cyclase (sGC) activity. Cinaciguat (BAY 58-2667) is a novel sGC activator that causes vasodilation, even in the presence of oxidized heme or heme-free sGC, but its hemodynamic effects have not been studied in the perinatal lung. We performed surgery on eight fetal (126 ± 2 days gestation) lambs (full term = 147 days) and placed catheters in the main pulmonary artery, aorta, and left atrium to measure pressures. An ultrasonic flow transducer was placed on the left pulmonary artery to measure blood flow, and a catheter was placed in the left pulmonary artery for drug infusion. Cinaciguat (0.1–100 μg over 10 min) caused dose-related increases in pulmonary blood flow greater than fourfold above baseline and reduced pulmonary vascular resistance by 80%. Treatment with 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), an sGC-oxidizing inhibitor, enhanced cinaciguat-induced pulmonary vasodilation by >120%. The pulmonary vasodilator effect of cinaciguat was prolonged, decreasing pulmonary vascular resistance for >1.5 h after brief infusion. In vitro stimulation of ovine fetal pulmonary artery smooth muscle cells with cinaciguat after ODQ treatment resulted in a 14-fold increase in cGMP compared with non-ODQ-treated cells. We conclude that cinaciguat causes potent and sustained fetal pulmonary vasodilation that is augmented in the presence of oxidized sGC and speculate that cinaciguat may have therapeutic potential for severe neonatal pulmonary hypertension.

Effect of implant duration on in vivo sensitivity of electromagnetic flow transducers

1979 ◽  
Vol 236 (3) ◽  
pp. H508-H512 ◽  
Author(s):  
C. A. Astley ◽  
A. R. Hohimer ◽  
R. B. Stephenson ◽  
O. A. Smith ◽  
F. A. Spelman
Keyword(s):  
Rhesus Monkeys ◽  
Initial Period ◽  
Dialysis Tubing ◽  
Flow Transducer ◽  
Electromagnetic Flow ◽  
Femoral Arteries ◽  
In Vitro Sensitivity

Twenty-three electromagnetic flow transducers with lumen diameters of 3.5-6.0 mm were implanted in rhesus monkeys and baboonss for 12 h to 120 days. Each flow transducer was calibrated 1) in vitro on dialysis tubing with saline before implantation, 2) in vivo the last day of the implant period, and 3) again in vitro after the flow transducer was recovered. Three other flow transducers were implanted on femoral arteries of baboon just central to an arteriovenous Silastic shunt, and were calibrated in vivo daily for 23-47 days. In vitro sensitivity was not affected by implant durations of up to 120 days. In vivo sensitivity fluctuated unpredictably for the first 3-4 wk of implant, after which it followed a systematic course that depended on the lumen size. In vivo sensitivity at any time during implant (after the initial period) could be accurately predicted by knowing either the in vitro sensitivity or the terminal in vivo sensitivity.

Investigation on a flow transducer using modified force sensing technique

2020 ◽  
Vol 14 (10) ◽  
pp. 1019-1028
Author(s):  
Saikat Kumar Bera ◽  
Pradip Kumar Sadhu
Keyword(s):  
Force Sensing ◽  
Flow Transducer

Control of resting bronchial hemodynamics in the awake dog

1993 ◽  
Vol 265 (2) ◽  
pp. H649-H660 ◽  
Author(s):  
E. Hennessy ◽  
S. White ◽  
T. van der Touw ◽  
A. Quail ◽  
W. Porges ◽  
...  
Keyword(s):  
Continuous Wave ◽  
Bronchial Artery ◽  
Sensory Nerve ◽  
Transmural Pressure ◽  
Low Flow ◽  
Flow Transducer ◽  
Beta Adrenoceptor ◽  
Continuous Wave Doppler ◽  
Pentobarbital Sodium Anesthesia ◽  
The Right

In the resting awake dog a continuous-wave Doppler flow transducer on the right bronchoesophageal artery inscribes a sharp early systolic spike and low flow in late systole and throughout diastole, indicating a highly resistive bed. An analysis of autonomic factors using intravenous, cumulative, and randomly applied cholinoceptor, beta 1- and beta 2-adrenoceptor, and alpha 1- and alpha 2-adrenoceptor antagonists indicates that the low vascular conductance is due to cholinoceptor and alpha 1- and alpha 2-adrenoceptor effects in a ratio 3.6:1. No beta-adrenoceptor tone is present. Sighing behavior invokes a transient (< 2 s) fall in intrapleural pressure (and thus rise in bronchovascular transmural pressure) of 10-30 mmHg, which is followed by a two- to threefold increase over 30 s in bronchial flow and conductance, an effect simulated in 50% of dogs when bronchovascular transmural pressure is acutely raised and maintained over 40-60 s by inflating an intra-aortic balloon distal to the origin of the bronchial artery. Autonomic blockade has no effect on bronchovascular dilatation evoked either by sighing or by balloon inflation. It is concluded that, in the resting bronchial circulation, there exists strong cholinoceptor and alpha-adrenoceptor-based vasoconstrictor activity which can be overpowered by strong nonadrenergic noncholinergic local vasodilator reflexes evoked by sudden changes in intrathoracic transmural pressure possibly acting on stretch-sensitive sensory nerve endings containing substance P, calcitonin gene-related peptide, and neurokinins. The tonic vasoconstrictor but not the sigh-evoked vasodilator effects are sensitive to pentobarbital sodium anesthesia.

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